Industrial processes are known in which one of the secondary outputs is a fluid, typically at high temperature. In order to exploit the energy stored in the fluid coming from a process, heat exchangers or other devices for energy recovery, in particular for heat absorption and exploitation, are commonly used.
In discontinuous industrial processes, the temperature of the fluid at the outlet is variable over time, typically with high temperature fluctuations, making the energy recovery devices unusable or poorly efficient. In such discontinuous processes the fluid, which can be air, water, molten salts or other, is commonly fed into a storage tank in order to uniformize as much as possible the temperature thereof. The fluid coming from the tank is then conveyed to the energy recovery devices or other utilities. However, the efficiency of such tanks is limited. In fact, while the height of the temperature peaks of the fluid is lowered, the fluctuation of the fluid temperature over time still remains of considerable entity. By such a conventional uniformization process, the fluid can be fed only to complex and/or large utilities.
Moreover, in the traditional uniformization processes, in order to obtain relatively low temperature fluctuations it is necessary to use large tanks. In particular, the higher the temperature fluctuations of the fluid at the inlet of the tank, the greater the tank size; it is also necessary to have a large distance between the inlet and the outlet of the tank, in order not to affect the temperature of the fluid at the outlet.
An example of a discontinuous process is the production of steel by electric arc furnace, where the amount of dissipated heat from outgoing fumes is very large and the high variability of the temperatures and of the flow rates of the fumes, due to the highly intermittent production process, makes the recovery technologies used unable to carry out large energy recoveries. In particular, by observing the trend of the temperature of the water extracted from a heat recovery system, associated to the melting cycle of steel in an electric arc furnace and fed to a storage tank, the high temperature peaks of water are clearly visible. Disadvantageously, however, also the temperature fluctuation of the water coming from the storage tank remains considerable.
Other examples of highly discontinuous processes are the processes associated with the crematoria, the basic oxygen processes BOF and the production of refractories.
A need is therefore felt to provide a process for uniformizing the temperature of a liquid coming from a discontinuous industrial process that is more efficient compared to the prior art processes. A need is also felt for a storage tank for uniformizing the temperature of a liquid, coming from a discontinuous industrial process which is usable with such a process, which is smaller in size compared to known tanks, which does not require expensive insulating coatings and which allows an efficient uniformization of temperature.